Pressure Washer NOT a Boiler 1

[EngBrad]

Thank you in advance to anyone who can help me here. I work for a company that manufacturers pressure washers, air compressors, etc. Several states are trying to tell us that we need to have our hot water pressure washer approved by ASME. We are arguing that we don't for 2 reasons.

1) Under ACT 85 regulation a boiler is defined as; “Any closed vessel in which water is heated, steam is generated, steam is superheated or any combination thereof under pressure or vacuum for use external to itself by the direct application of heat from the combustion of fuels or from electricity”. A pressure washer is not a closed vessel in which steam is generated. The water is first pumped through a heat exchanger, and then heated to about 200 deg. F. Water starts to change to vapor at 212 deg. F, when the temperature reaches 375 deg. F then 50% of the water by volume is heated to steam. Since pressure washers do not generate steam, use a closed vessel and use a pump to develop pressure not steam, the definition does not apply.

2) Section I Rules for Construction of Power Boilers
PG 2.3 “It is not the intent of these rules to cover coil-type hot water boilers without any steam space where water flashes into steam when released through a manually operated nozzle for cleaning machinery, equipment, buildings, etc., unless one of the following limitations is exceeded:
(a) ¾” diameter tubing or pipe size with no drums or headers attached;
(b) nominal water containing capacity not exceeding 6 gallons;
(c) water temperature not exceeding 350 deg. F;
(d) steam not generated within the coil;
Steam cleaners exempt by this classification shall be provided with adequate relief valves and controls.”

I am new to this area of regulation. Is there something I am missing?

Thanks,
Brad

 

[metengr]

Most likely, you need to look at ASME B&PV Code, Section IV. If you are exempt from ASME B&PV Code, you should be exempt from State laws regarding boiler/pressure vessel regulation.

 

[zdas04]

I couldn't tell where the quotes ended and your description began. Is the heated water container closed or not? Does it increase in pressure to values above 15 psig or not? If it does then it could very well be subject to either the boiler code or the pressure vessel code.

If the state saying that the container is subject to the boiler code, then it might very well be less expensive to get a code stamp on it than the cost to have a lawyer fight them in court.

David

 

[fireguy519345]

If everything works like it is designed, your pressure washer may not generate steam. What happens when the pressure switch sticks in the on postion, on my pw, steam is produced. My machine also has a hi-limit switch that when it fails, allows my pw to produce steam. Should the unloader fail, and the gun is closed, I have a closed system.

 

[EngBrad]

fireguy519345,

That is why a hot water pressure washer has so many safety features. That way no one failure could cause a problem. Should the unloader fail and the gun is closed (as you state), the system would continue to develop pressure until the pressure relief setting is met (usually 4000 or 6000 psi depending the pressure setting of the system). If that fails, then the hi-limit would shut off the burner when the its temperature is met. If that fails, a temperature related burst disk will open releasing pressure to decrease the temperature. If that fails, the seals and packing inside the pump would begin to leak. And if that is not enough, we have hydrostatic tested our coil which contain the heated water. We have had the coil material up to 16,000 psi+ without a leak. That is a 4x safety factor over the units pressure relief valve. UL1776 only requires 2x the pressure relief valve.

With all of the safety features involved, the customer has plenty of warning that something is wrong with the machine. The probability of all the safety features failing at the same is very small.

Brad

 

[vpl]

This is my opinion only but if "several" (i.e., more than two, less than four) states are trying to tell you that you need to have our hot water pressure washer approved by ASME, you may be fighting an uphill battle, depending on how many "several" actually is. One state you might be able to successfully argue with them that you're correct. With multiple states, the probability is that there will be at least one who will not back down. In the end, it doesn't matter if you're "right," if the state won't let your products be manufactured/sold/used (whatever the reason is that you're getting state approval).

Patricia Lougheed

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[EngBrad]

I agree. The trade association we belong to has a technical committee (which I am on) that is working with ASME and the states to make sure we are exempt. It's just taking time to convince them.